Recruitment of receptors and ion channels to the postsynaptic membrane is the last step in synapse formation. Many of these proteins interact directly or indirectly with postsynaptic density-95 (PSD95)/Discs large/zona occludens-1 (PDZ) proteins, thus linking them to the postsynaptic scaffold and providing a mechanism for both retaining the protein at the synapse and keeping its proximity to signaling molecules known to associate with PDZ proteins (Wang et al. 2006, Morimura et al. 2006, Ko et al. 2006, Nourry et al. 2003, Kim & Sheng 2004, Montgomery et al. 2004, Sheng and Kim 2011). The synaptic adhesion-like molecules (SALM) family belongs to the superfamily of leucine-rich repeat (LRR)-containing adhesion molecules, alternatively referred to as LRFN (leucine-rich repeat and fibronectin III domain-containing) is synapse adhesion molecule linked to NMDA and AMPA receptors. It includes five known members (SALMs 1-5 or LRFN1-5), which have been implicated in the regulation of neurite outgrowth and branching, and synapse formation and maturation. SALM proteins are distributed to both dendrites and axons in neurons (Ko et al. 2006, Wang et al. 2006, Sebold et al. 2012). The family members, SALM1-SALM5, have a single transmembrane (TM) domain and contain extracellular leucine-rich repeats, an Ig C2 type domain, a fibronectin type III domain, and an intracellular postsynaptic density-95 (PSD-95)/Discs large/zona occludens-1 (PDZ) binding domain, which is present on all members except SALM4 and SALM5 (Ko et al. 2006, Wang et al.2006, Morimura et al. 2006).